Fast render animation?
As a first you need to know what is your priority: time or quality? You can't have both.

This is very complex "problem" and need a lot of study. What is good in one situation may not be good in another. 
Generally:

In "Sampling": 


set Clamp to higher value
use "Branched Path Tracing" - check noise in every pass in compositor and adjust Samples by render pass. 


In "Light Paths": 


turn off caustic.
reduce light bounces. 


In "Performance":


set Tilles according to your hardware (usually 64x64 for CPU, 256x256 for GPU).
tick "Persistent images" if your textures does not change in full length of animation
try using "Spatial Splits".


In Material node editor:
Use "Light path" for determine rays you don't need. For example disable shadow ray in glass can speed up render quite a lot.

I mentioned only most used features. There is not a general "golden rule" that work always and in every case. All settings depend of your scene and your preferences. 

BTW: render animation about 30 hours is not unusual.